The art of encapsulation has been known for many years, particularly for the production of unit dosage forms containing various pharmaceutical products. Normally, such pharmaceutical capsules are composed of gelatin or some modification thereof, which is fabricated essentially into two different forms, namely, the so-called hard gelatin capsule and the soft gelatin capsule.
It is also known that conventional soft gelatin capsules are a preferred from of administration for medicaments and similar products; especially liquids, pastes, solids dispersed in liquids, or dry solids. Soft gelatin capsules also possess particular advantages for substances which require total protection from air and light, because the gelatin is completely sealed around the contents. An important example is for the encapsulation of vitamins, which has resulted in a high degree of stability thereof.
Hard gelatin capsules are also known in the art, and are generally formed from two distinct parts, namely the “cap” and the “body”, fitting one into the other so as to form the complete capsule. The cap and the body are manufactured by the same process consisting of immersing in a gelatin solution the end of a mandrel whose form corresponds to the inner volume of the cap or of the body, then withdrawing the mandrel from the solution and letting the layer of gelatin thus deposited dry, which is then removed like a glove finger. Hard shell capsules so formed have problems of leakage and do not provide adequate protection from air and light
Soft gelatin capsules, now more commonly known as softgels, have been well known and widely used for many years. Softgels generally comprise an outer shell primarily made of gelatin, a plasticizer, and water, and a fill contained within the shell. The fill may be selected from any of a wide variety of substances that are compatible with the gelatin shell. Softgels are widely used in the pharmaceutical industry as an oral dosage form containing many different types of pharmaceutical and vitamin products. In addition to use as an oral dosage form for drugs and vitamins, soft gelatin capsules or softgels are also designed for use as suppositories for rectal or vaginal use. Other uses are for topical and ophthalmic preparations and the like. The cosmetic industry also uses softgels as a specialized package for various types of perfumes, oils, shampoos, skin creams and the like. Softgels are available in a great variety of sizes and shapes, including round shapes, oval shapes, oblong shapes, tube shapes and other special types of shapes such as stars. The finished capsules or softgels can be made in a variety of colors. Also, opacifiers may be added to the shell.
The process for making softgel capsules includes the step wherein the gelatin shell and the fill material come together to form Softgel capsules. It takes place in a closed environment called clean room where the relative humidity is around 20%. The gelatin shell and fill material are brought together simultaneously in the encapsulation machine.
The process is basically performed as follows: a pump delivers the warm gelatin over two chilled drums which are located at both opposite sides of the machine, through a spreader box that sits over each drum. The warm liquid gelatin flows over the drums and this transforms the liquid gelatin into two solid ribbons of gel. The left and right ribbons pass over rollers which feed them through two die rolls. These die rolls determine the shape and size of softgels and cut the Softgel shell from the ribbons as they turn around.
Simultaneously, a sensitive and high accuracy positive displacement pump delivers the fill material into a heated wedge which sits between rotary dies. This wedge injects the fill material into the die cavities between ribbons just right before the die rolls cut the ribbons and seal the two halves together. Warm just formed softgels slide gently through a chute onto a conveyor belt which carries them to the tumble dryer where cooling and drying process takes place.
In more specific detail, typical soft encapsulation machines form at least two flexible gelatin sheets or ribbons by cooling molten gelatin on separate drums then lubricating and guiding the sheets into communication with each other over co-acting dies while simultaneously dispensing a desired quantity of fill material between the sheets in synch with cavities in the outer surfaces of the dies to produce soft capsules. The encapsulation machines typically utilize gearing to control the relative rotations of the various components and fill mechanisms to synchronize the operation of these various components. The synchronization of these various components, however, can vary depending upon a variety of factors, such as the particular dies used, the number of cavities and the size of the cavities on the dies, and the type of material used to form the sheets. To change the synchronization of the various components, mechanical gears are required to be changed to obtain the desired ratios and synchronization of these components. The changing of gears, however, is time intensive. Additionally, the use of mechanical gears provides finite gear ratios which limit the synchronization of the various components to the mechanical gears that are available. Thus, it would be advantageous to provide a capsule machine wherein the synchronization and rates at which the various components operate can be altered without the necessity of changing gears. Additionally, it would be advantageous if the synchronization between the various components can be infinite to thereby allow more precise synchronization between the various components. It would also be advantageous to allow various components, such as the fill mechanism, to be adjusted independently of the other components while the machine is running to allow for adjustments of the timing of fill material inserted into each of the soft capsules.
During the operation of the capsule making machine, the contact between the adjacent dies can be adjusted by the operator of the capsule making machine. Typically, the operator is able to move one of the dies closer to the other die so that the pressure or force exerted on the sheets passing between the adjacent dies can be adjusted. Such adjustments, typically are mechanical adjustments made by fluid actuators, such as pneumatic cylinders. The operator is able to adjust the pneumatic pressure thereby altering the force the dies exert on one another and on the sheets. This adjustability allows an operator to customize the pressure to ensure that quality soft capsules are produced. However, the dies are susceptible to premature failure and/or wear when the pressure or force between the two dies is more than that required to produce acceptable soft capsules. Thus, it would be advantageous to monitor/record the pressure applied to the dies so that quality capsules are produced without inducing excessive wear or premature wear on the dies.
A material fill mechanism is used to supply the fill material that is encapsulated within the soft capsules. When the fill material is a liquid, such as a liquid medication or die for a paint ball capsule, the fill mechanism includes a plurality of positive displacement plunger-type pumps that are arranged in a housing above the dies. The plunger-type pumps are positioned on a yoke that moves linearly in a reciprocating motion to allow the plunger-type pump to fill with the liquid fill material on one stroke and subsequently discharge the liquid fill material on the other stroke. A valving arrangement between opposing pumps is utilized to control the discharge and filling of the pumps. The valve arrangement includes a sliding member that moves linearly back and forth in a direction generally perpendicular to the linear motion of the yoke. The discharge of the liquid fill material into the sheets as they are passing through the dies is coordinated with the operation of the dies to insure that the timing of the injection of the liquid fill material is synchronized with the cavities on the dies. Typically, this synchronization has been performed through the use of mechanical gears that link the timing of the stroke to the rotation of the dies. Thus, in order to adjust the synchronization a mechanical gear change is required which is time consuming. Additionally, the timing is limited to a finite number of gear ratios as determined by the gears that are available.
The sliding member of the valving mechanism requires lubrication. Typically, the lubrication is provided by a lubricating pump with its own separate drive. However, the use of a separate drive to operate the lubricating pump adds additional complexity and components to the capsule machine. Thus, it would be advantageous if a motion of the slide member and/or the yoke could be utilized to drive the lubrication pump.
The pumps are typically contained within a housing that is filled with a lubricating oil that is used to lubricate the sliding member. The pumps, however, can leak around their seals and contaminate the lubricating oil with the leaking fill material. Contamination of the oil requires a time consuming and possibly difficult clean up and can cause the lubricating oil to not perform as designed thereby increasing the wear on the sliding surfaces and decreasing the life span of the sliding surfaces. Thus, it would be advantageous to capture any fill material that leaks from the pumps and deter or prevent the liquid fill material from contaminating the lubricating oil within the pump housing.
The pumps are typically driven by a drive mechanism that is also located within the pump housing. Because the drive mechanism is located in the pump housing, it is possible for liquid fill material that leaks from the pumps to contaminate not only the lubrication oil but also the drive mechanism. When switching from one fill material to another, the pump and all of the components in the pump housing are required to be thoroughly cleaned to remove all contamination. The locating of the drive mechanism within the pump housing provides additional components that must also be cleaned when changing the fill material. Thus, it would be advantageous to separate the drive mechanism from the pump housing to reduce the components that are required to be cleaned when changing fill material.
The soft capsules produced by the encapsulation machine are transported from the encapsulation machine to a dryer to additionally dry the soft capsules and to make them into final form. The soft capsules are transported from the encapsulation machine to the dryer by a conveyor that extends along the front of the encapsulation machine. The conveyor can be contaminated by the fill material during operation of the encapsulation machine. When it is desired to switch the product being produced on the encapsulation machine, the conveyor must be removed from the encapsulation machine and cleaned to remove any contaminates thereon. The conveyor is driven by a motor that is attached to the conveyor. When it is necessary to remove the conveyor for cleaning, the motor must also be taken with the conveyor which makes it more difficult to remove and transport the conveyor and requires additional time to disconnect the motor from the encapsulation machine. Thus, it would be advantageous to provide a conveyor that can be easily and quickly disconnected from the motor and removed from the encapsulation machine without the motor. The present invention provides an encapsulation machine that overcomes the above-described disadvantages of typical encapsulation machines.
Thus, it would be advantageous to provide a fill mechanism that is synchronized with the dies without the use of a mechanical linkage. Additionally, it would be advantageous if such synchronization could be adjusted during operation of the encapsulation machine to fine tune the synchronization and the production of capsules.
Applicant is aware of the following publications briefly discussed below. U.S. Pat. No. 1,970,396 features a method and machine for producing soft gelatin capsules in an automated process. The method involves the formation of two gelatin sheets or films through the use of a gravity fed spreader box, cooling the liquid gelatin on two separate webs, then lubricating and guiding the two sheets into communication with each other between two co-acting dies while simultaneously dispensing the proper amount of medicine or other filling material between the sheets in registration with half cavities in the outer surface of the dies.
U.S. Pat. No. 5,761,886 discloses an apparatus for forming capsules that provides rotary dies that are independently moveable and the ability to vary the speed of the dies during the formation of a single capsule. The '886 device also utilizes independently controlled casting drums to reduce “set-up” time and provide better quality control. Even though the '886 patent discloses a very sophisticated encapsulation machine, it still utilizes a gravity fed spreader box for formation of the encapsulating ribbon.
Other patents relating to encapsulation techniques which disclose the use of spreader boxes to create the film or ribbon on a casting drum include U.S. Pat. Nos. 2,288,327; 2,774,988; 5,246,638; 5,735,105; and 6,022,499.